<?php
/**
 * CMssqlSchema class file.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Christophe Boulain <Christophe.Boulain@gmail.com>
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2011 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * CMssqlSchema is the class for retrieving metadata information from a MS SQL Server database.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @author Christophe Boulain <Christophe.Boulain@gmail.com>
 * @version $Id: CMssqlSchema.php 3270 2011-06-14 17:41:34Z qiang.xue $
 * @package system.db.schema.mssql
 * @since 1.0.4
 */
class CMssqlSchema extends CDbSchema
{
    const DEFAULT_SCHEMA='dbo';

    /**
     * @var array the abstract column types mapped to physical column types.
     * @since 1.1.6
     */
    public $columnTypes=array(
        'pk' => 'int IDENTITY PRIMARY KEY',
        'string' => 'varchar(255)',
        'text' => 'text',
        'integer' => 'int',
        'float' => 'float',
        'decimal' => 'decimal',
        'datetime' => 'datetime',
        'timestamp' => 'timestamp',
        'time' => 'time',
        'date' => 'date',
        'binary' => 'binary',
        'boolean' => 'bit',
    );

    /**
     * Quotes a table name for use in a query.
     * A simple table name does not schema prefix.
     * @param string $name table name
     * @return string the properly quoted table name
     * @since 1.1.6
     */
    public function quoteSimpleTableName($name)
    {
        return '['.$name.']';
    }

    /**
     * Quotes a column name for use in a query.
     * A simple column name does not contain prefix.
     * @param string $name column name
     * @return string the properly quoted column name
     * @since 1.1.6
     */
    public function quoteSimpleColumnName($name)
    {
        return '['.$name.']';
    }

    /**
     * Compares two table names.
     * The table names can be either quoted or unquoted. This method
     * will consider both cases.
     * @param string $name1 table name 1
     * @param string $name2 table name 2
     * @return boolean whether the two table names refer to the same table.
     */
    public function compareTableNames($name1,$name2)
    {
        $name1=str_replace(array('[',']'),'',$name1);
        $name2=str_replace(array('[',']'),'',$name2);
        return parent::compareTableNames(strtolower($name1),strtolower($name2));
    }

    /**
     * Resets the sequence value of a table's primary key.
     * The sequence will be reset such that the primary key of the next new row inserted
     * will have the specified value or 1.
     * @param CDbTableSchema $table the table schema whose primary key sequence will be reset
     * @param mixed $value the value for the primary key of the next new row inserted. If this is not set,
     * the next new row's primary key will have a value 1.
     * @since 1.1.6
     */
    public function resetSequence($table,$value=null)
    {
        if($table->sequenceName!==null)
        {
            $db=$this->getDbConnection();
            if($value===null)
            $value=$db->createCommand("SELECT MAX(`{$table->primaryKey}`) FROM {$table->rawName}")->queryScalar();
            $value=(int)$value;
            $name=strtr($table->rawName,array('['=>'',']'=>''));
            $db->createCommand("DBCC CHECKIDENT ('$name', RESEED, $value)")->execute();
        }
    }

    private $_normalTables=array();  // non-view tables
    /**
    * Enables or disables integrity check.
    * @param boolean $check whether to turn on or off the integrity check.
    * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
    * @since 1.1.6
    */
    public function checkIntegrity($check=true,$schema='')
    {
        $enable=$check ? 'CHECK' : 'NOCHECK';
        if(!isset($this->_normalTables[$schema]))
        $this->_normalTables[$schema]=$this->findTableNames($schema,false);
        $db=$this->getDbConnection();
        foreach($this->_normalTables[$schema] as $tableName)
        {
            $tableName=$this->quoteTableName($tableName);
            $db->createCommand("ALTER TABLE $tableName $enable CONSTRAINT ALL")->execute();
        }
    }

    /**
     * Loads the metadata for the specified table.
     * @param string $name table name
     * @return CMssqlTableSchema driver dependent table metadata. Null if the table does not exist.
     */
    protected function loadTable($name)
    {
        $table=new CMssqlTableSchema;
        $this->resolveTableNames($table,$name);
        //if (!in_array($table->name, $this->tableNames)) return null;
        $table->primaryKey=$this->findPrimaryKey($table);
        $table->foreignKeys=$this->findForeignKeys($table);
        if($this->findColumns($table))
        {
            return $table;
        }
        else
        return null;
    }

    /**
     * Generates various kinds of table names.
     * @param CMssqlTableSchema $table the table instance
     * @param string $name the unquoted table name
     */
    protected function resolveTableNames($table,$name)
    {
        $parts=explode('.',str_replace(array('[',']'),'',$name));
        if(($c=count($parts))==3)
        {
            // Catalog name, schema name and table name provided
            $table->catalogName=$parts[0];
            $table->schemaName=$parts[1];
            $table->name=$parts[2];
            $table->rawName=$this->quoteTableName($table->catalogName).'.'.$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
        }
        elseif ($c==2)
        {
            // Only schema name and table name provided
            $table->name=$parts[1];
            $table->schemaName=$parts[0];
            $table->rawName=$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
        }
        else
        {
            // Only the name given, we need to get at least the schema name
            //if (empty($this->_schemaNames)) $this->findTableNames();
            $table->name=$parts[0];
            $table->schemaName=self::DEFAULT_SCHEMA;
            $table->rawName=$this->quoteTableName($table->schemaName).'.'.$this->quoteTableName($table->name);
        }
    }

    /**
     * Gets the primary key column(s) details for the given table.
     * @param CMssqlTableSchema $table table
     * @return mixed primary keys (null if no pk, string if only 1 column pk, or array if composite pk)
     */
    protected function findPrimaryKey($table)
    {
        $kcu='INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
        $tc='INFORMATION_SCHEMA.TABLE_CONSTRAINTS';
        if (isset($table->catalogName))
        {
            $kcu=$table->catalogName.'.'.$kcu;
            $tc=$table->catalogName.'.'.$tc;
        }

        $sql = <<<EOD
		SELECT k.column_name field_name
			FROM {$this->quoteTableName($kcu)} k
		    LEFT JOIN {$this->quoteTableName($tc)} c
		      ON k.table_name = c.table_name
		     AND k.constraint_name = c.constraint_name
		   WHERE c.constraint_type ='PRIMARY KEY'
		   	    AND k.table_name = :table
				AND k.table_schema = :schema
EOD;
        $command = $this->getDbConnection()->createCommand($sql);
        $command->bindValue(':table', $table->name);
        $command->bindValue(':schema', $table->schemaName);
        $primary=$command->queryColumn();
        switch (count($primary))
        {
            case 0: // No primary key on table
                $primary=null;
                break;
            case 1: // Only 1 primary key
                $primary=$primary[0];
                break;
        }
        return $primary;
    }

    /**
     * Gets foreign relationship constraint keys and table name
     * @param CMssqlTableSchema $table table
     * @return array foreign relationship table name and keys.
     */
    protected function findForeignKeys($table)
    {
        $rc='INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS';
        $kcu='INFORMATION_SCHEMA.KEY_COLUMN_USAGE';
        if (isset($table->catalogName))
        {
            $kcu=$table->catalogName.'.'.$kcu;
            $rc=$table->catalogName.'.'.$rc;
        }

        //From http://msdn2.microsoft.com/en-us/library/aa175805(SQL.80).aspx
        $sql = <<<EOD
		SELECT
		     KCU1.CONSTRAINT_NAME AS 'FK_CONSTRAINT_NAME'
		   , KCU1.TABLE_NAME AS 'FK_TABLE_NAME'
		   , KCU1.COLUMN_NAME AS 'FK_COLUMN_NAME'
		   , KCU1.ORDINAL_POSITION AS 'FK_ORDINAL_POSITION'
		   , KCU2.CONSTRAINT_NAME AS 'UQ_CONSTRAINT_NAME'
		   , KCU2.TABLE_NAME AS 'UQ_TABLE_NAME'
		   , KCU2.COLUMN_NAME AS 'UQ_COLUMN_NAME'
		   , KCU2.ORDINAL_POSITION AS 'UQ_ORDINAL_POSITION'
		FROM {$this->quoteTableName($rc)} RC
		JOIN {$this->quoteTableName($kcu)} KCU1
		ON KCU1.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
		   AND KCU1.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
		   AND KCU1.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
		JOIN {$this->quoteTableName($kcu)} KCU2
		ON KCU2.CONSTRAINT_CATALOG =
		RC.UNIQUE_CONSTRAINT_CATALOG
		   AND KCU2.CONSTRAINT_SCHEMA =
		RC.UNIQUE_CONSTRAINT_SCHEMA
		   AND KCU2.CONSTRAINT_NAME =
		RC.UNIQUE_CONSTRAINT_NAME
		   AND KCU2.ORDINAL_POSITION = KCU1.ORDINAL_POSITION
		WHERE KCU1.TABLE_NAME = :table
EOD;
        $command = $this->getDbConnection()->createCommand($sql);
        $command->bindValue(':table', $table->name);
        $fkeys=array();
        foreach($command->queryAll() as $info)
        {
            $fkeys[$info['FK_COLUMN_NAME']]=array($info['UQ_TABLE_NAME'],$info['UQ_COLUMN_NAME'],);

        }
        return $fkeys;
    }


    /**
     * Collects the table column metadata.
     * @param CMssqlTableSchema $table the table metadata
     * @return boolean whether the table exists in the database
     */
    protected function findColumns($table)
    {
        $columnsTable="INFORMATION_SCHEMA.COLUMNS";
        $where=array();
        $where[]="TABLE_NAME='".$table->name."'";
        if (isset($table->catalogName))
        {
            $where[]="TABLE_CATALOG='".$table->catalogName."'";
            $columnsTable = $table->catalogName.'.'.$columnsTable;
        }
        if (isset($table->schemaName))
        $where[]="TABLE_SCHEMA='".$table->schemaName."'";

        $sql="SELECT *, columnproperty(object_id(table_schema+'.'+table_name), column_name, 'IsIdentity') as IsIdentity ".
			 "FROM ".$this->quoteTableName($columnsTable)." WHERE ".join(' AND ',$where);
        if (($columns=$this->getDbConnection()->createCommand($sql)->queryAll())===array())
        return false;

        foreach($columns as $column)
        {
            $c=$this->createColumn($column);
            if (is_array($table->primaryKey))
            $c->isPrimaryKey=in_array($c->name, $table->primaryKey);
            else
            $c->isPrimaryKey=strcasecmp($c->name,$table->primaryKey)===0;

            $c->isForeignKey=isset($table->foreignKeys[$c->name]);
            $table->columns[$c->name]=$c;
            if ($c->autoIncrement && $table->sequenceName===null)
            $table->sequenceName=$table->name;
        }
        return true;
    }

    /**
     * Creates a table column.
     * @param array $column column metadata
     * @return CDbColumnSchema normalized column metadata
     */
    protected function createColumn($column)
    {
        $c=new CMssqlColumnSchema;
        $c->name=$column['COLUMN_NAME'];
        $c->rawName=$this->quoteColumnName($c->name);
        $c->allowNull=$column['IS_NULLABLE']=='YES';
        if ($column['NUMERIC_PRECISION_RADIX']!==null)
        {
            // We have a numeric datatype
            $c->size=$c->precision=$column['NUMERIC_PRECISION']!==null?(int)$column['NUMERIC_PRECISION']:null;
            $c->scale=$column['NUMERIC_SCALE']!==null?(int)$column['NUMERIC_SCALE']:null;
        }
        elseif ($column['DATA_TYPE']=='image' || $column['DATA_TYPE']=='text')
        $c->size=$c->precision=null;
        else
        $c->size=$c->precision=($column['CHARACTER_MAXIMUM_LENGTH']!== null)?(int)$column['CHARACTER_MAXIMUM_LENGTH']:null;
        $c->autoIncrement=$column['IsIdentity']==1;

        $c->init($column['DATA_TYPE'],$column['COLUMN_DEFAULT']);
        return $c;
    }

    /**
     * Returns all table names in the database.
     * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
     * If not empty, the returned table names will be prefixed with the schema name.
     * @param boolean $includeViews whether to include views in the result. Defaults to true.
     * @return array all table names in the database.
     * @since 1.0.4
     */
    protected function findTableNames($schema='',$includeViews=true)
    {
        if($schema==='')
        $schema=self::DEFAULT_SCHEMA;
        if($includeViews)
        $condition="TABLE_TYPE in ('BASE TABLE','VIEW')";
        else
        $condition="TABLE_TYPE='BASE TABLE'";
        $sql=<<<EOD
SELECT TABLE_NAME, TABLE_SCHEMA FROM [INFORMATION_SCHEMA].[TABLES]
WHERE TABLE_SCHEMA=:schema AND $condition
EOD;
        $command=$this->getDbConnection()->createCommand($sql);
        $command->bindParam(":schema", $schema);
        $rows=$command->queryAll();
        $names=array();
        foreach ($rows as $row)
        {
            if ($schema == self::DEFAULT_SCHEMA)
            $names[]=$row['TABLE_NAME'];
            else
            $names[]=$schema.'.'.$row['TABLE_SCHEMA'].'.'.$row['TABLE_NAME'];
        }

        return $names;
    }

    /**
     * Creates a command builder for the database.
     * This method overrides parent implementation in order to create a MSSQL specific command builder
     * @return CDbCommandBuilder command builder instance
     */
    protected function createCommandBuilder()
    {
        return new CMssqlCommandBuilder($this);
    }

    /**
     * Builds a SQL statement for renaming a DB table.
     * @param string $table the table to be renamed. The name will be properly quoted by the method.
     * @param string $newName the new table name. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB table.
     * @since 1.1.6
     */
    public function renameTable($table, $newName)
    {
        return "sp_rename '$table', '$newName'";
    }

    /**
     * Builds a SQL statement for renaming a column.
     * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method.
     * @param string $name the old name of the column. The name will be properly quoted by the method.
     * @param string $newName the new name of the column. The name will be properly quoted by the method.
     * @return string the SQL statement for renaming a DB column.
     * @since 1.1.6
     */
    public function renameColumn($table, $name, $newName)
    {
        return "sp_rename '$table.$name', '$newName', 'COLUMN'";
    }

    /**
     * Builds a SQL statement for changing the definition of a column.
     * @param string $table the table whose column is to be changed. The table name will be properly quoted by the method.
     * @param string $column the name of the column to be changed. The name will be properly quoted by the method.
     * @param string $type the new column type. The {@link getColumnType} method will be invoked to convert abstract column type (if any)
     * into the physical one. Anything that is not recognized as abstract type will be kept in the generated SQL.
     * For example, 'string' will be turned into 'varchar(255)', while 'string not null' will become 'varchar(255) not null'.
     * @return string the SQL statement for changing the definition of a column.
     * @since 1.1.6
     */
    public function alterColumn($table, $column, $type)
    {
        $type=$this->getColumnType($type);
        $sql='ALTER TABLE ' . $this->quoteTableName($table) . ' ALTER COLUMN '
        . $this->quoteColumnName($column) . ' '
        . $this->getColumnType($type);
        return $sql;
    }
}
